How Long Is Stomach Flu Contagious?

Learn how long you should stay home

The stomach flu is often contagious from the time you're exposed to whatever is causing it. It remains so the whole time you're sick (when you're most contagious) and for quite a while after you start feeling better. Altogether, this can add up to a few weeks.

Exactly how long you are contagious depends on what you're infected with. There are several pathogens that can cause the stomach flu.

This article looks at the various durations for which the stomach flu is contagious and how long you should stay home if you get it.

African American woman suffering stomach cramps - stock photo

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Stomach Flu Contagiousness by Cause

Some viruses and bacteria that cause the stomach flu, or gastroenteritis, may be contagious for longer or shorter periods than others.

This is because of variations in how long it takes to develop symptoms, how long you have them once you get them, and how long you are contagious after symptoms have resolved.

You may very well pass on the stomach flu to someone else before you even know you have it or well after you think it has passed.

Here's a look at four common causes of the stomach flu and how long they are contagious by stage.

INFECTION EXPOSURE TO SYMPTOM ONSET SYMPTOMATIC STAGE CONTAGIOUS POST-SYMPTOMS
Norovirus 1-2 days 1-3 days Up to 2 weeks
Rotavirus 2 days 3-8 days Up to 10 days
Campylobacter 2-5 days 7 days 1 week or more
Escherichia coli (E. coli) 3-4 days 5-10 days Up to 10 days
Source: Centers for Disease Control and Prevention

How Long Should You Stay Home With the Stomach Flu?

Follow your healthcare provider's advice on how long you should stay home with the stomach flu.

Generally speaking, those with the stomach flu should stay home for the duration of their illness and between 24 hours and 48 hours after symptoms go away.

Anyone who's running a fever is definitely contagious. Even without a fever, stomach viruses are easy to spread.

You may be tempted to go to work or send your child to school after a night that's free of vomiting or diarrhea. However, it's important to wait a full 24 hours after the last episode.

Though it's possible, symptoms are unlikely to come back if they've been absent for that period.

How Stomach Flu Is Spread

Stomach flu is usually spread by the fecal-oral route—accidental ingestion of infected stool.

This can come from:

  • Consuming contaminated food or water
  • Touching contaminated objects or surfaces
  • Coming into close contact with an infected person

When to Call a Healthcare Provider

While you do what you can to prevent spreading the stomach flu to others, be sure you are also taking care of yourself by resting and hydrating.

Call a healthcare provider or go to your nearest urgent care center if you have the stomach flu and you:

  • Cannot keep down fluids for more than 24 hours
  • Have a fever over 104 degrees F
  • Have been vomiting for more than two days
  • Have signs of severe dehydration
  • Have bloody stools
  • Have bloody vomit

Summary

Stomach viruses are highly contagious. You can spread them before symptoms begin and for up to two weeks after you recover.

It's advisable to stay home for 24 to 48 hours after your vomiting, diarrhea, and fever have gone away to make sure you're symptom-free.

The best way to prevent the spread of stomach flu viruses like norovirus and rotavirus is to wash your hands frequently and isolate yourself when sick.

Frequently Asked Questions

  • What is stomach flu?

    Stomach flu is a term popularly used to describe gastroenteritis. This intestinal infection can be caused by bacteria, viruses, and certain types of fungi and parasites.

  • Is the stomach flu really the flu?

    No. The actual flu is a respiratory illness caused by the influenza virus. Viral and other stomach illnesses are commonly called the stomach flu despite the misnomer.

  • What are the symptoms of stomach flu?

    Stomach flu typically causes diarrhea and vomiting as well as abdominal cramping. Viral infections often include fever, fatigue, headache, and muscle pain. Bacterial infections sometimes cause bloody stools.

  • How long does stomach flu last?

    Generally, the symptoms of gastroenteritis develop suddenly within one to five days of exposure. They usually resolve within a week.

  • How can I prevent the stomach flu?

    Frequent, proper handwashing and surface cleaning are the best ways to prevent stomach flu. A rotavirus vaccine is available for small children. The vaccine can help prevent this very serious cause of severe diarrhea in kids.

5 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Graves NA. Acute gastroenteritis. Prim Care. 2013 Sep;40(3):727-41. doi:10.1016/j.pop.2013.05.006

  2. MedlinePlus. Gastroenteritis (stomach flu).

  3. Stuempfig ND, Seroy J. Viral gastroenteritis. In: StatPearls.

  4. Sattar SBA, Singh S. Bacterial gastroenteritis. In: StatPearls.

  5. Centers for Disease Control and Prevention. Prevent the spread of norovirus.

Additional Reading

By Kristina Duda, RN
Kristina Duda, BSN, RN, CPN, has been working in healthcare since 2002. She specializes in pediatrics and disease and infection prevention.